furnish batch interface with trait

Signed-off-by: Jason Volk <jason@zemos.net>

src/database/map/qry_batch.rs

@@ -0,0 +1,63 @@
+use std::{fmt::Debug, sync::Arc};
+
+use conduwuit::{
+	implement,
+	utils::{
+		stream::{automatic_amplification, automatic_width, WidebandExt},
+		IterStream,
+	},
+	Result,
+};
+use futures::{Stream, StreamExt, TryStreamExt};
+use serde::Serialize;
+
+use crate::{keyval::KeyBuf, ser, Handle};
+
+pub trait Qry<'a, K, S>
+where
+	S: Stream<Item = K> + Send + 'a,
+	K: Serialize + Debug,
+{
+	fn qry(self, map: &'a Arc<super::Map>) -> impl Stream<Item = Result<Handle<'_>>> + Send + 'a;
+}
+
+impl<'a, K, S> Qry<'a, K, S> for S
+where
+	Self: 'a,
+	S: Stream<Item = K> + Send + 'a,
+	K: Serialize + Debug + 'a,
+{
+	#[inline]
+	fn qry(self, map: &'a Arc<super::Map>) -> impl Stream<Item = Result<Handle<'_>>> + Send + 'a {
+		map.qry_batch(self)
+	}
+}
+
+#[implement(super::Map)]
+#[tracing::instrument(skip(self, keys), level = "trace")]
+pub(crate) fn qry_batch<'a, S, K>(
+	self: &'a Arc<Self>,
+	keys: S,
+) -> impl Stream<Item = Result<Handle<'_>>> + Send + 'a
+where
+	S: Stream<Item = K> + Send + 'a,
+	K: Serialize + Debug + 'a,
+{
+	use crate::pool::Get;
+
+	keys.ready_chunks(automatic_amplification())
+		.widen_then(automatic_width(), |chunk| {
+			let keys = chunk
+				.iter()
+				.map(ser::serialize_to::<KeyBuf, _>)
+				.map(|result| result.expect("failed to serialize query key"))
+				.map(Into::into)
+				.collect();
+
+			self.db
+				.pool
+				.execute_get(Get { map: self.clone(), key: keys, res: None })
+		})
+		.map_ok(|results| results.into_iter().stream())
+		.try_flatten()
+}